Ferromagnetic ceramic inductance core



United States Patent 2,728,054 FERROMAGNETIC CERAMIC INDUCTANCE COREErnst Albers-Schoenberg, Metuchen, N. J., assignor to Steatite ResearchCorporation, Keasbey, N. J., a corporation of Delaware ApplicationSeptember 20, 1951, Serial No. 247,507 3 Claims. (Cl. 336-83) Thisinvention relates to core of the type having small non-ferrornagneticgaps.

air gap and of the coil.

Another object of the a gapped ferromagnetic invention therefore corewith a is to provide permanent and inis then ready to be assembled Theceramic ferromagnetic formula of x O.yFe2O3 in materials have thegeneral which M" and in which x: y is approximately 1:1. The novelfeatures characteristic parts slightly separated.

Figure 2 is a view similar to Figure 1 of a modified form of cup core.

In order to illustrate the invention a cup type of core 2,728,054Patented Dec. 20, 1955 has been shown but it will be obvious from areading of the following description that the principle of theincorresponding cup part 20.

The coil part to make the core parts in this way.

In the modification shown in Figure 2 the two parts are madesubstantially identical. In this way it is easier to obtain a largergap.

The following example illustrates how the cores are made.

Example A zinc-nickel ferrite composition containing about 17% of zincoxide, about 13% of nickel oxide, about 65 of ferric oxide and about 2%ure 1 or 2). mately 2200 F. After cooling, the outer ange 12 of flint,about 65% of a ground frit, int, 40% borax, Other known ceramic glazescan of course that the maturing tembelow the fusion temperature ofapplied the piece If invariable gap of the glaze 14.

Since the various parts of core have flat contacting surface.

I claim: l. A ferromagnetic inductance core of the type having a gap ofnite length in the magnetic material thereof, said core being formed inat least two parts, the said two parts having at least two separatesubstantially planar contacting areas therebetween, a first one of saidparts consisting essentially of a ceramic ferromagnetic ferrite, a firstof said contacting lareas of said rst part making ferromagnetic contactwith the corresponding contacting surfaces of a second of said partswhen the parts are asscmbled with a coil thereon, a second of saidcontacting areas of said first part containing a ceramic glaze whichcontacts a corresponding area of said second part when the parts areassembled whereby the said glaze forms an accurate and invariable gapbetween the corresponding second contacting areas of the two parts.

2. The device of claim l in which said core consists of two parts, eachconsisting essentially of ceramic ferromagnetic material and eachcomprising a glaze coating on one contacting area.

3. The device of claim 1 in which said core consists of two,similarly-formed, cup-shaped parts, each having the second of saidcontacting areas at the end of a continuous ange surrounding but spacedfrom the rst pair of contacting areas.

References Cited in the le of this patent UNITED STATES PATENTS

1. A FERROMAGNETIC INDUCTANCE CORE OF THE TYPE HAVING A GAP OF FINITELENGTH IN THE MAGNETIC MATERIAL THEREOF, SAID CORE BEING FORMED IN ATLEAST TWO PARTS, THE SAID TWO PARTS HAVING AT LEAST TWO SEPARATESUBSTANTIALLY PLANAR CONTACTING AREAS THEREBETWEEN, A FIRST ONE OF SAIDPARTS CONSISTING ESSENTIALLY OF A CERAMIC FERROMAGNETIC FERRITE, A FIRSTOF SAID CONTACTING AREAS OF SAID FIRST PART MAKING FERROMAGNETIC CONTACTWITH THE CORRESPONDING CONTACTING SURFACES OF A SECOND OF SAID PARTSWHEN THE PARTS ARE AS SEMBLED WITH A COIL THEREON, A SECOND OF SAIDCONTACTING AREAS OF SAID FIRST PART CONTAINING A CERAMIC GLAZE WHICHCONTACTS A CORRESPONDING AREA OF SAID SECOND PART WHEN THE PARTS AREASSEMBLED WHEREBY THE SAID GLAZE FORMS AN ACCURATE AND INVARIABLE GAPBETWEEN THE CORRESPONDING SECOND CONTACTING AREAS OF THE TWO PARTS.